Jiang Miao, Liu Gaozhan, Zhang Qiang, Zhou Dong, Yao Xiayin
Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, P. R. China.
Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, P. R. China.
ACS Appl Mater Interfaces. 2021 Apr 28;13(16):18666-18672. doi: 10.1021/acsami.1c00511. Epub 2021 Apr 20.
Due to the intrinsic poor ionic/electronic conductivities of LiS, it is a great challenge to realize high-rate all-solid-state lithium-sulfur batteries (ASSLSBs) with long cyclic performance. Herein, ultrasmall LiS (∼15 nm) is evenly deposited on a carbon nanotube (CNT) a facile liquid-phase method to address these issues. The unique structure of the LiS deposited on a CNT composite cathode can improve ionic/electronic conductivities of LiS effectively and relieve the generated internal stress/strain during cycling. Specifically, the resultant Li/75%LiS-24%PS-1%PO/LiGePS/LiS-53%CNT ASSLSBs show a reversible capacity of 651.4 mAh g under 1.0C at 60 °C after 300 cycles and even at a much higher cathode load of 5.08 mg cm, a high discharge capacity of 556 mAh g can still be obtained under 0.1C after 20 cycles. The outstanding electrochemical performances are also attributed to the high diffusion coefficient of LiS-53%CNT, which is 39 times that of pristine LiS. This work presents an efficient procedure to design cathode materials with high ionic/electronic conductivities and paves the way for the successful commercialization of high-rate ASSLSBs.
由于硫化锂（LiS）固有的离子/电子导电率较差，要实现具有长循环性能的高倍率全固态锂硫电池（ASSLSBs）是一项巨大挑战。在此，通过一种简便的液相方法将超小的LiS（约15纳米）均匀沉积在碳纳米管（CNT）上，以解决这些问题。沉积在CNT复合阴极上的LiS的独特结构可以有效提高LiS的离子/电子导电率，并缓解循环过程中产生的内应力/应变。具体而言，所得的Li/75%LiS-24%PS-1%PO/LiGePS/LiS-53%CNT全固态锂硫电池在60℃下1.0C倍率下经过300次循环后可逆容量为651.4 mAh g，甚至在更高的阴极负载5.08 mg cm²下，经过20次循环后在0.1C倍率下仍可获得556 mAh g的高放电容量。优异的电化学性能还归因于LiS-53%CNT的高扩散系数，其是原始LiS的39倍。这项工作提出了一种设计具有高离子/电子导电率的阴极材料的有效方法，并为高倍率全固态锂硫电池的成功商业化铺平了道路。
